Chapter 5 - Life processes Flashcards
What are living beings?
Organisms that show all the characteristics of life such as growth, movement, reproduction, and respiration.
What are the basic life processes necessary for survival?
- Nutrition
- Respiration
- Transportation
- Excretion
What is nutrition?
The process of intake of food from outside the body to grow, develop, and synthesize proteins.
How is nutrition fulfilled in different organisms?
Some use simple food materials like carbon dioxide and water, while others use complex food materials that are broken down into simpler ones.
What role do enzymes play in nutrition?
Enzymes are biocatalysts that help in breaking down complex substances into simpler ones.
What are the two classifications of modes of nutrition?
- Autotrophic
- Heterotrophic
Define autotrophic nutrition.
Nutrition in which organisms prepare their own food from inorganic raw materials like carbon dioxide and water.
What is photosynthesis?
The process of production of food from carbon dioxide and water in the presence of sunlight and chlorophyll.
What are the events of photosynthesis?
- Chlorophyll absorbs light energy
- Light energy is converted to chemical energy
- Water molecule splits into hydrogen and oxygen
- Carbon dioxide reduces to carbohydrates
What are chloroplasts?
Green dots in some cells of leaves that contain chlorophyll and are the site of photosynthesis.
How do plants obtain carbon dioxide?
Through tiny pores called stomata present on the surface of the leaves.
What regulates the opening and closing of stomata?
Guard cells.
What is the function of guard cells?
They regulate the opening and closing of stomatal pores.
What type of nitrogen is used by plants?
Nitrogen is taken in the form of inorganic nitrates or as organic compounds prepared by bacteria from atmospheric nitrogen.
What is heterotrophic nutrition?
The mode of nutrition in which an organism depends on other living organisms for food.
What are the three types of heterotrophs based on food type?
- Carnivores: eat only animals (e.g. lion, snake)
- Herbivores: eat only plants (e.g. rabbit, elephant)
- Omnivores: eat both plants and animals (e.g. crow, dog)
What is an example of an organism that breaks down food outside the body?
Yeast and mushrooms.
How do unicellular organisms take in food?
Food is taken by the entire surface.
How does Amoeba ingest food?
Using temporary finger-like projections that fuse over the food particle to form a food vacuole.
What is the alimentary canal?
A long tube extending from the mouth to the anus through which nutrition in human beings takes place.
What is the role of salivary amylase in digestion?
It breaks down starch, a complex molecule, into sugar.
What is peristaltic movement?
The rhythmic contraction of muscles in the alimentary canal that pushes food forward.
What substances are secreted by gastric glands in the stomach?
- Hydrochloric acid
- Pepsin
- Mucus
What does mucus do in the stomach?
It protects the inner lining of the stomach from the action of acid under normal conditions.
How does the guard cells open and close?
When the plant is in need of carbon dioxide, the guard cells gain water from the neighboring epidermal cells through endosmosis and swells, opening the stomatal pore.
How do desert plants perform photosynthesis?
During night, desert plants absorb carbon dioxide and form an intermediate. Then during day time when the stomata is closed to prevent loss of water, they use this stored carbon dioxide to perform photosynthesis.
